Electrical switch contacts having a spring and a contact element connected to the spring, along with methods for producing such contacts, are known in the prior art. The contacts are fastened to brackets to form contact assemblies, which perform switching functions in electric switches such as relays or contactors. The switches have drive devices which move the contacts to electrically connect with or release from counter contacts.
In certain applications, such as metering relays, high demands are made of the current-carrying capacity of the contacts. An electric current is transmitted from the bracket via the spring to the contact element, and on to the counter contact element. The contact element is designed to have optimal electric transmission properties, while the spring is optimized to provide a force releasing the contact from the counter contact. The spring is thus generally produced from a material that has the best possible spring properties and sufficient electrical conductivity, such as CuCrSiTi.
The spring and contact element should be connected to one another as securely as possible in order to guarantee the best possible current transfer between them. However, particularly in light of the constant endeavours to miniaturize contact assemblies, it is increasingly difficult to produce a sufficiently stable connection between the spring and the contact element. As an alternative to known rivet connections, single-layer springs are also welded to contact elements. Electrical transfer resistance in the weld is lower, which is also reflected in a thermal advantage, leading to greater long-term connection stability between the contact element and spring. However, welding has not been used with multi-layered springs, such as coated springs, because welding has not been sufficiently precise in the connection between spring layers.